Tube changing device



April 26, 1938. M PQHONTISCH 2,115,373

TUBE CHANGING DEVICE Filed Dec. 1, 1934 ATTORNEY Patented Apr. 26, 1938UNITED STATES rare OFFICE TUBE CHANGING DEVICE ticn of GermanyApplication December 1, 1934, Serial No. 755,536 In Germany December 15,1933 2 Claims.

In many cases it has been found necessary to provide spare or standbytubes in devices equipped with electron tubes in such a way that insidethe briefest possible time, and, optionally, without necessitating anychanges in the circuit of the device, will thus be rendered capable oftaking over the work of other tubes. It has been suggested for thispurpose to fixedly build the sockets for the two tubes into the set andto provide a switch whereby the standby tube may be cut in the circuitin lieu of the one previously in operation. Quite apart from thediificulties liable to result from the use of switches becausev ofdefective contact-making, switches of this kind are rather complicatedand therefore also rather costly especially when they are called upon tochange the connections of more than one tube at the same time. Thereexists this further drawback that the use of such a circuit organizationrequires wiring and the disposition of leads likely to conduce todisturbances for reasons of spurious and undesired couplings.

Hence, it is an object of this invention to secure the two tubes or tubegroups in a part which is capable of being actuated by a handle, knob,or the like in such a manner that the tubes acting as spare tubes may beintroduced in lieu of the previous ones into the socket or socketsfixedly associated with the receiver assembly.

It is a further object of this invention to permit a tube located withina closed casing to be removed from its socket and quickly replaced byanother tube of the same type from a position external to the casing andwithout opening it. Other objects will be apparent to those skilled inthe art as the description thereof proceeds. For a better understandingof the invention reference is made to the accompanying drawing, inwhich:

Fig. 1 is a front view of a tube changing device made according to myinvention,

Fig. 2 is a top view of the device of Fig. l, and

Fig. 3 is a sectional view through the lines 3-3 of Fig. 1.

Referring to the drawing, i denotes the mounting or base plate of theset into which the tube socket 2 is recessed. Tubes 3 and 4 which areintended for being mutually substituted are secured by the aid ofterminal screws 5 in recesses of a plate 6. Arranged on this plate arealso guide pins 1 and a spindle 8 of preferably circular cross-section,the latter at the same time serving the purpose of moving thetube-supporting plate 0, A part 9 of the spindle 8 is of non-circularcross-sectional shape, but preferably formed in a way as indicatedsectionally in Fig. 3. The said part is guided by a suitably formedrecess in the base plate I and is so disposed on the spindle 8 mtturning of the plate 6 is impossible as long as the prongs of the plugof one of the two tubes 3, 4, are in the holes of the socket. Indeed, itis only when the plate 6 carrying the tubes has been sufficiently raisedby the aid of the handle l0 that a rotation through an angle of 180degrees and thus substitution of tube 4 will be practicable. The pins 1engage in a corresponding opening ll of the mounting board and thusafiord safer guidance.

What may be particularly pointed out is that the exemplified embodimenthereinbefore described is to serve merely as an illustration to explainthe basic idea of the invention, and that the same by no means isconfined to the use in connection with the described arrangement. Infact, the arrangement may be readily so designed that instead of onetube 3 an entire group or bank of tubes may be replaced by standbytubes. The supporting of the mounting plate 6 and the movement thereofwill then be capable of a great many modifications. For instance, therotation need not be just 180 degrees, in fact, the pivot may be soplaced that the movement of the plate will be small and merely begoverned by the size of the tubes.

The movement after the lifting out of the tube socket by no means needsto be rotary in nature, for, as a matter of fact, it could also betranslational or shifting.

The use of the basic idea of the invention is of importance even whenthe point is to insure the replacement of tubes inside a closed casingwithout any manipulation in the latter and without even opening thecase. A problem of this kind is involved, for instance, when a tubestage is accommodated inside a thermostat, and if substitution of a tubeis then to be accomplished without an incidental alteration of theworking conditions. In this instance, spindle 8 is brought out acrossthe thermostat by the aid of a heatinsulating and packing stufiing boxor gland. The guide pins 1 could then be disposed outside case and couldbe provided with marks or means indicating which particular tube is inthe circuit at a given instant after a circuit-change has been effected.

It is moreover not necessary to insure a tube substitution manually;indeed, it may be effected by tele-control or tele-mechanic meansthrough the agency or relays or automatically, and independence upon acharacteristic operating quantity of the tube which happens to be incircuit. I 7 7 r a V For use in an arrangement of the kind heredisclosed are suited nearly. all types of tube. If

an electrode has been brought out at the top end, then this particularelectrode will in both" 7 'tubes be united permanently by a movablecable 1 Withthe circuits. r

I claim:

1. In combination, a stationary tube socketfa 7 base p1ate, a shaftmounted forrotation rand endwise movement, an arm carried by said shaft,a

' plurality of tubes carried by said armandihaving their bases adaptedto register with said socket, an operating handle secured to said shaft,said base plate being provided with a non-circular c aperture, a membersecured to said shaft and V a shaped to conform to said aperture andenter'the' same when one of said tube'bases is in engage ment with saidsocket and additional means carried by said arm arranged to align one ofsaid tube bases with said socket before engagement of said base'a'ndsocket.

2. In combination, a stationary tube'socket, a" 'base plate'havinganaperture'therein, a shaft carried by said shaft and at, least one pin'project 10" to register with said socket, an operating handle.

ing from said arm parallel to said shaft and ar- 7 ranged to enter theaperture in said base plate I before a tube enters said socket, said pinand aperture being arranged to guide the tubeinto V the socket. r

r MAX POHONTSCI L

